1. Field of the Invention
This invention relates to circuit control systems and more particularly to remotely operated circuit control systems.
2. Description of the Prior Art
In modern aircraft in order to reduce the weight and cost of heavy, expensive aviation cable between power supply busses and electric loads via the flight engineer's or pilot's station, it is known to use remotely controlled circuit devices such as remotely controlled circuit breakers located near the power supply with small control units positioned in the cockpit and interconnected with the breaker itself by light, inexpensive control wires in order to reduce the length of power lead runs between the power bus equipment and the loads. These remote control breakers function to protect against overloads (both of the short-circuit and low level or ultimate trip types), as well as contactors which are resettable and trippable from the control unit.
One such remote controlled circuit breaker is described and claimed in U.S. Patent No. 3,651,436 which issued to Lawrence E. Cooper and Robert W. Peterson and is assigned to the assignee of the instant invention. While that circuit breaker has been very effective and reliable, assembly is more complex and time consuming than desirable thereby adding to the cost of the device. Further, there is a continuing need to decrease the size and weight of such circuit breakers and to increase their life expectancy. Another example is described and claimed in U.S. Pat. No. 4,317,094 in which a solenoid and pawl arrangement can be used with conventional circuit breakers to make them remotely controllable. The applicability of this latter example is however, somewhat limited since the force levels required for lower current ratings due to the size limitations imposed by the airplane structure. That is, if it were to be used at current levels of up to 75 amperes for example, the size of the solenoid required would be larger than acceptable.